Causes and Prevention of Gas in Dogs

Causes of Canine Gas

Gas is a normal component of gastrointestinal contents in all canines. The primary cause of intestinal gas is “aerophagia,” which simply is the ingestion (or gulping) of air when swallowing. Gas also forms in the GI tract from the interaction of alkaline food (high pH), stomach acids and digestive enzymes; from bacterial metabolism and fermentation of digesta in the lower bowel; and from diffusion of gas out of circulating blood. Gas normally is removed from the gastrointestinal tract either up through the esophagus by burping (eructation; “belching”), or out through the anus by “passing gas”) (flatulence; “farting” (slang)).
Excess gas can be caused by a number of things, including:

Gastrointestinal disease. When dogs develop any form of malabsorption or maldigestion disorder, the undigested or unabsorbed food products remain available for fermentation by intestinal bacteria, which produces gas. Causes can include inflammatory bowel disease, gastrointestinal neoplasia (cancer), internal parasites, exocrine pancreatic insufficiency, small intestinal bacterial overgrowth, irritable bowel syndrome and bacterial or viral enteritis. Other diseases that cause an inability to break down and absorb nutrients can also cause flatulence, because the nonabsorbed material moves through the intestinal tract and becomes subject to abnormal fermentation in the lower bowel (also called the colon).

Excessive bacterial fermentation. Certain dietary substances are poorly digestible or poorly absorbable by domestic dogs, such as soy products, beans, peas, excess fat, spices, spoiled food, pectin and lactose. For example, adult dogs typically cannot digest foods that contain milk products, because as dogs mature they stop producing lactase, the enzyme necessary to break down lactose. As a result, adult dogs tend to become flatulent shortly after eating milk products. Diets that are high in fermentable fiber, such as oat bran, can also cause flatulence.

Excessive swallowing of air (aerophagia). Dogs that gulp their food – especially when multiple dogs are fed in the same area such that competition for food develops – tend to ingest abnormally large amounts of air when they swallow. Strenuous exercise, particularly when followed by gulping of food or water, can also cause a build-up of gastrointestinal gas. Finally, any respiratory disorder that causes rapid breathing can contribute to aerophagia in domestic dogs.

Dietary changes or indiscretion. Dogs often develop gas when their diets are changed, especially if those changes are not gradual. They also tend to be gassy after episodes of so-called “dietary indiscretion,” such as when they get into the garbage, eat a bag of cat food, eat rotten or spoiled food, eat mice or other rodents or otherwise ingest things that are not part of a normal canine diet.

Prevention of Gas in Dogs

Canine flatulence can almost always be prevented, or at least managed. Some useful approaches include:

Change the diet. A highly digestible diet that is low in fat and fiber can decrease gastric gas production. Sometimes, changing the source of protein and/or carbohydrates in the diet can help a gassy dog as well. There are many high-quality dog foods – both in kibble and canned form – that contain novel protein or carbohydrate sources and that are highly digestible without containing high levels of fat or fiber. A veterinarian is the best one to discuss proper nutrition and dietary management for any particular animal.

Raised feeders. Many breeders, owners and veterinarians feed their dogs from raised feeders. Elevating a dog’s food and water bowls is thought to reduce its intake of air when swallowing, especially in dogs prone to gulping their food. This subject is somewhat controversial, as there have not been sufficient repeatable scientific studies to prove the efficacy of feeding raised versus feeding at ground level in terms of managing intestinal gas.

Stones in bowls. For rapid-eaters, some experts recommend adding large rocks or stones to the food bowl, to force the dog to eat more slowly. Obviously, these stones must be big enough so that there is no way for the dog to swallow them.

Feed separately. Where competitive eating may be contributing to excess air gulping and gas formation, affected dogs should be fed separately from other household pets, in a quiet, private spot.

Avoid feeding after exercise. Owners should wait an hour or so after their dog has engaged in vigorous exercise before feeding a full meal.

Multiple small meals. It is usually better to feed a dog several small meals daily rather than a single large one, for a number of reasons. In addition to preventing the build-up of excessive gas (simply because there are fewer food products in the stomach available for fermentation at one time), multiple small meals are easier to digest and help regulate the digestive system. Many experts also believe that feeding a dog smaller meals more frequently can reduce its chances of developing gastric dilatation and volvulus, or “bloat.”

Increased activity. Dogs, like people, usually benefit from an active lifestyle. Regular, low-impact moderate exercise stimulates motility in the gastrointestinal tract, which helps move gas along and regulates the passage of gas and feces.

Special Notes

Flatulence does not mean the passage of foul-smelling gas. It simply refers to excess gas formation in the GI tract that passes out through the anus. Most gastrointestinal gas is composed of oxygen, nitrogen, hydrogen, methane and carbon dioxide, all of which are odorless.